Not really a drivetrain question but...
To cut to the chase - Does it make much sense to upgrade to a 4-2-1 performance header while still retaining the stock exhaust (cat, mufflers...)?
Has anyone done this?
Or is it just a pointless counter performance upgrade that will produce no gain. Or even retard performance?
I would imagine the stock mufflers might be too restrictive(?). I don't know....

Honestly; I'd prefer my exhaust tone to be/remain "quiet" as stock...
However; I'm also interested in fabbing my own exhaust as I am currently researching "absorption mufflers" or turbo mufflers. If it's at all possible.

My current 04 R53 mods are:
Stock head (pre-facelift)
15% SC pulley
3" CAI
Siemens 380cc injectors
Stock coil w/NGK wires and BKR7 colder plugs
Adrian tune
Max boost ~ 15 - 15.5 psi

I'm a total newbie when it comes to performance mods for a Mini. Specifically my R53. So a little kind, informative, education thrown my way would be greatly appreciated

Thanks.

 

Why retain the stock exhaust? The resonated Milltek cat-back system has a deeper tone at idle than stock and maybe just a little louder at WOT with a pleasant note. It is a very nice, high quality exhaust system. The flow of the stock exhaust system seems circuituous in that it feeds into the passerger side muffler, then across to the driver side muffler and then to the tips. The Milltek system splits from the center pipe into each muffler and then each muffler has its own tip.

Like this:


vs the stock exhaust system:



For headers, it seems the RMW shorty header is the way to go for performance gains but I don't have conclusive evidence to back that up, just "word on the street" type talk. I too, am interested in a header for my car and I am leaning towards the RMW header but there are less expensive options (Milltek, Racing Dynamics, etc...) to consider as well.

My mods are similar to yours except 17% pulley, Milltek catback system and not tuned yet. I don't know why I'm dragging my feet on the tune. I guess it's "after I install (name the next mod), I'll get it tuned" type thing.

 

Likely you guys have seen my combo of header & hi-flow cat (circa 2006 with actual manufacturer unknown) with full Milltek resonated cat-back. I haven't heard a W11 engine with just the Milltek for comparison but highly suspect significantly louder than with OEM header. In the end, I'm very pleased with my setup now that I've sorted all that out. Most aftermarket headers aren't CARB compliant thus might not pass mandatory emissions testing plus visual inspection for the presence of those components where applicable. Here in AZ, testing is required in Maricopa and Pima Counties (greater metro Phoenix and Tucson) but not in Gila County where I live. OTOH, the original owner of mine lives in an eastern Maricopa County suburb subject to that testing, yet successfully passed periodic testing, including the morning of my purchase (he wasn't aware not required in my county or town). Just some factors for consideration WRT $$ and installation effort, only to run afoul of emissions requirements...

 

Very good points to consider.
Thank you both for your input.

I've also done quite a bit of searching and reading before posting my initial question/thread. Most of which resulted in conversations among the BMW, Mustang and Corvette crowd. A different animal than specific to Mini. But a well a balanced read on performance pros and cons vs opinion and experience.I also recently came across this old NAM thread . The last 2wo entries (one was the video) gave me a pretty good indication of what I might expect with respect to exhaust note in addition the appropriate mufflers...

Sufficed to say; I think I'll leave well enough alone...(for now).
My stock exhaust is physically sound and rust free condition for a 20y/o southern climate car and I like it's subtle factory resonance. There really is no immediate need to replace it.
I'm just not in a financial (or logistical) position to drop $800++ into a complete Milltek or JCW performance exhaust system at the moment.

But here's the skinny -
I was recently presented with a great price on a low milage (5K) genuine Milltek header w/flex pipe from a guy I met while at a local salvage yard. A deal (1/4 $$ - new), really too good to pass up.

I'll buy the header from him and store it until I decide later as what to do.

Thanks!

 

Yep, I have an XForce no cat sitting here, but see no pressing need to install it unless I’m going to change exhaust to something else (or at least one ball it) or when I have engine out.

 

I don't see why you wouldn't at least give the 4-2-1 a try with the stock cat back. I did something similar on my WRX Everything is free flowing up front (header, up pipe and down pipe) and mated to the stock exhaust.It's just barely louder than the stock and the performance improvement is there. I'm sure it would be more with a better exhaust but it does make an improvement.

Also, if you are researching for a quiet but performance oriented exhaust set up you might want to check out what some of the Buick Grand National folks were doing. They were doing a three (3) muffler set up to be super quiet and still knock of 10sec passes in the qtr. (might be limited on space with the mini, but I suppose it could be possible.)

 

Thanks for that supporting thought @Boostmaster .
I was thinking the same ("why not give it a try?") - as a project mod for this coming Spring.

Unfortunately: As the saying goes - "you snooze. you loose". I waited too long grappling with the idea and missed the opportunity to score that ($80) Milltek.
I didn't get a response from the seller until this morning. He sold it to his buddy for $100 just before X-mas.
I then quickly (but not quick enough) considered the alternate one in the NAM marketplace that had been listed for weeks...but that one too has also recently been sold.

Oh well.
As "the old man" said to Ralphie (hoping Santa had brought him the Red Rider bb gun), - "There's always next Christmas".

 

^^Truth! I had the chance at a lightly used 4-2-1 header a few years back. Guy said it was too loud and was giving it away for like $75. I snoozed on it and missed out! My current one cost $399! So yeah, I feel your pain. Best bet is to wait for those holiday sales- that's how I scored my current exhaust. Not as cheap as you might have had, but cheaper than retail.

 

Please report back. I'm trying to find ways to eke more power out of a quiet JCW, and a cam/header is a next logical step. The fear of a significant noise increase is what has held me back and there is little information available on header use with stock exhaust systems. I feel the cam would not be worth it without the additional flow of the header, so it everything seems to hinge on that.

Well, E85 is also on the bucket list. But lack of local tuning knowledge has put that on the backburner.

 

^^ You don't need "local" tuning knowledge. Adrian is the man (somewhere in Romania?) He's tuned tons of cars here and just did mine a few months ago. It was easy, fast and inexpensive and the result was exceptional.

 

Yeah I've heard nothing but good things about him, but after a few attempts at picking his brain about E85 I haven't really gotten anywhere. I still plan on going that route, but it's been deprioritized thanks to a lack of progress with him and too many other projects.